package org.springframework.data.web;
import java.lang.reflect.Method;
import java.util.List;
import javax.annotation.Nonnull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.core.MethodParameter;
import org.springframework.data.domain.Pageable;
import org.springframework.hateoas.Link;
import org.springframework.hateoas.server.MethodLinkBuilderFactory;
import org.springframework.hateoas.server.core.MethodParameters;
import org.springframework.hateoas.server.mvc.WebMvcLinkBuilderFactory;
import org.springframework.lang.Nullable;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;
import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;
public class PagedResourcesAssemblerArgumentResolver implements HandlerMethodArgumentResolver {
private static final Logger LOGGER = LoggerFactory.getLogger(PagedResourcesAssemblerArgumentResolver.class);
private static final String SUPERFLOUS_QUALIFIER = "Found qualified {} parameter, but a unique unqualified {} parameter. Using that one, but you might want to check your controller method configuration!";
private static final String PARAMETER_AMBIGUITY = "Discovered multiple parameters of type Pageable but no qualifier annotations to disambiguate!";
private final HateoasPageableHandlerMethodArgumentResolver resolver;
private final MethodLinkBuilderFactory<?> linkBuilderFactory;
public PagedResourcesAssemblerArgumentResolver(HateoasPageableHandlerMethodArgumentResolver resolver,
@Nullable MethodLinkBuilderFactory<?> linkBuilderFactory) {
this.resolver = resolver;
this.linkBuilderFactory = linkBuilderFactory == null ? new WebMvcLinkBuilderFactory() : linkBuilderFactory;
}
@Override
public boolean supportsParameter(MethodParameter parameter) {
return PagedResourcesAssembler.class.equals(parameter.getParameterType());
}
@Nonnull
@Override
public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) {
UriComponents fromUriString = resolveBaseUri(parameter);
MethodParameter pageableParameter = findMatchingPageableParameter(parameter);
if (pageableParameter != null) {
return new MethodParameterAwarePagedResourcesAssembler<>(pageableParameter, resolver, fromUriString);
} else {
return new PagedResourcesAssembler<>(resolver, fromUriString);
}
}
@Nullable
private UriComponents resolveBaseUri(MethodParameter parameter) {
Method method = parameter.getMethod();
if (method == null) {
throw new IllegalArgumentException(String.format("Could not obtain method from parameter %s!", parameter));
}
try {
Link linkToMethod = linkBuilderFactory.linkTo(parameter.getDeclaringClass(), method).withSelfRel();
return UriComponentsBuilder.fromUriString(linkToMethod.getHref()).build();
} catch (IllegalArgumentException o_O) {
return null;
}
}
@Nullable
private static MethodParameter findMatchingPageableParameter(MethodParameter parameter) {
Method method = parameter.getMethod();
if (method == null) {
throw new IllegalArgumentException(String.format("Could not obtain method from parameter %s!", parameter));
}
MethodParameters parameters = MethodParameters.of(method);
List<MethodParameter> pageableParameters = parameters.getParametersOfType(Pageable.class);
Qualifier assemblerQualifier = parameter.getParameterAnnotation(Qualifier.class);
if (pageableParameters.isEmpty()) {
return null;
}
if (pageableParameters.size() == 1) {
MethodParameter pageableParameter = pageableParameters.get(0);
MethodParameter matchingParameter = returnIfQualifiersMatch(pageableParameter, assemblerQualifier);
if (matchingParameter == null) {
LOGGER.info(SUPERFLOUS_QUALIFIER, PagedResourcesAssembler.class.getSimpleName(), Pageable.class.getName());
}
return pageableParameter;
}
if (assemblerQualifier == null) {
throw new IllegalStateException(PARAMETER_AMBIGUITY);
}
for (MethodParameter pageableParameter : pageableParameters) {
MethodParameter matchingParameter = returnIfQualifiersMatch(pageableParameter, assemblerQualifier);
if (matchingParameter != null) {
return matchingParameter;
}
}
throw new IllegalStateException(PARAMETER_AMBIGUITY);
}
@Nullable
private static MethodParameter returnIfQualifiersMatch(MethodParameter pageableParameter,
@Nullable Qualifier assemblerQualifier) {
if (assemblerQualifier == null) {
return pageableParameter;
}
Qualifier pageableParameterQualifier = pageableParameter.getParameterAnnotation(Qualifier.class);
if (pageableParameterQualifier == null) {
return null;
}
return pageableParameterQualifier.value().equals(assemblerQualifier.value()) ? pageableParameter : null;
}
}